1. Technical Field
The present invention relates to a semiconductor apparatus, and more particularly, to a semiconductor apparatus that is capable of operating in a dynamic voltage scaling mode.
2. Related Art
Various semiconductor apparatuses receive external voltages VDD from outside and generate internal voltages with different levels from that of the external voltage VDD. Some of the internal voltages (hereinafter, referred to as internal high voltages) may be higher than the external voltages VDD supplied from outside of the semiconductor apparatuses. A semiconductor memory apparatus such as a DRAM generates an internal high voltage, particularly, a pumping voltage VPP (hereinafter, the internal high voltage will be exemplified as the pumping voltage VPP), as a voltage for driving word lines.
The internal high voltage VPP is generated by repeating the steps of feeding back the current level of an internal high voltage VPP, comparing the current level of the internal high voltage VPP with the level of a target voltage, and increasing the level of the internal high voltage VPP according to the comparison result. In order to perform the operation of feeding back the current level of the internal high voltage VPP and comparing the current level of the internal high voltage VPP with the level of the target voltage, a pumping voltage detection apparatus is used.
The pumping voltage detection apparatus detects the level of the internal high voltage VPP, determines whether the internal high voltage VPP has reached the target voltage, and generates a pumping enable signal. When the level of the internal high voltage VPP is higher than the level of the target voltage, the pumping voltage detection apparatus typically deactivates the pumping enable signal. However, when the level of the internal high voltage VPP is lower than the level of the target voltage, the pumping voltage detection apparatus activates and outputs the pumping enable signal. The pumping enable signal generated as described above is inputted to a pumping circuit of a semiconductor apparatus and is used to control a pumping operation of the internal high voltage VPP.
Some of the recently developed semiconductor apparatuses, DRAMs in particular, employ a dynamic voltage scaling mode to reduce power consumption. Since a low external voltage VDD is supplied in the dynamic voltage scaling mode as opposed to a normal mode, power consumption of the semiconductor apparatus may be reduced.
With the recent development of semiconductor apparatuses after a DDR3 technology, DRAMs in particular, for example, there has been proposed a method of additionally receiving an external high voltage VPPEXT as another supply voltage supplied from outside of the semiconductor apparatus as well as the external voltage VDD. The external high voltage VPPEXT has a level higher than that of the external voltage VDD, and is used for internal circuits of the semiconductor apparatus which require a higher voltage than the external voltage VDD. The semiconductor apparatus additionally generates the internal high voltage VPP, separately from the external high voltage VPPEXT.
In the dynamic voltage scaling mode, the supply voltages such as the external voltage VDD and the external high voltage VPPEXT supplied from outside of the semiconductor apparatus are lower than those in the normal mode. The semiconductor apparatus operates using the lower external voltage VDD and the lower external high voltage VPPEXT as compared with the normal mode, resulting in the reduction in power consumption. When a lower internal high voltage VPP is generated in the dynamic voltage scaling mode as compared with the normal mode, the above-mentioned power consumption reduction effect may be further increased. However, since the internal high voltage VPP with the same level is generated in the dynamic voltage scaling mode and the normal mode in the conventional art without detecting the external high voltage VPPEXT, power may be unnecessarily consumed.